At OpenWorld, Oracle's annual user conference, Ellison, the company's chairman, spent much of his keynote touting the company new database and bashing Amazon's rival product. To hear Ellison tell it, Oracle 18c is not only faster, cheaper, and better than Amazon's Redshift database, it can do things that Redshift can't do.

Amazon begged to differ on Monday. A representative for the company's Amazon Web Services cloud unit not only called Ellison's claims "factually incorrect," but accused him of being full of blarney.

"Most people know already that this sounds like Larry being Larry," the representative said. "No facts, wild claims, and lots of bluster."

One of the chief bones of contention was Ellison's claim that Amazon's Redshift database isn't "elastic." Elasticity refers to the ability to quickly and efficiently adapt to different sized workloads.

Contrary to Ellison, the AWS representative insisted that Redshift is indeed "elastic."

"Customers can resize their clusters whenever they want or can scale compute separately from storage," the representative said.

In addition to bashing Amazon, Ellison used his time on stage to tout Oracle 18c, a new autonomous database. With those two things together, Ellison made one thing clear: Oracle considers AWS to be its biggest competitor.

While AWS is the industry leader in cloud computing, Oracle has long-held the reins in databases. In 1979, Oracle became the first company to commercially release what's known as a relational database — now the industry standard.

AWS released its first database product, the Amazon Relational Database Service, in 2009. Amazon's database service can be used on top of Oracle's database.

Oracle's dominance has slipped in recent years, as AWS's developed a reputation for having cheap and quick cloud and database offerings, and Ellison has started to address the growing threat from Amazon. His OpenWorld keynote last year was similarly focused on how Oracle's cloud is better than Amazon's.

"You know when I'm talking about Amazon, I'm being nothing but fair. You can count on that," Ellison said at the time.

Whether or not customers agree is of great monetary importance to Ellison. He and Oracle's co-CEOs, Safra Catz and Mark Hurd, are under tremendous pressure to increase the company's cloud revenues and raise its stock price to $80 a share. They will only receive their stock awards — which represents the bulk of their compensation — if they meet their goals by 2020.

So far, it's not looking good. Following a disappointing quarterly forecast on September 15, Oracle's stock price plunged 8%, and it has yet to recover.